(a) Technical Field
The present application relates to a touch panel including a touch sensor and a display device including the same.
(b) Description of the Related Art
A flat panel display (FPD), such as an organic light emitting diode (OLED) display, a liquid crystal display (LCD), and an electrophoretic display (EPD) includes a field generating electrode and an electro-optical active layer. As the electro-optical active layer, the organic light emitting diode display includes an organic emission layer, the liquid crystal display includes a liquid crystal layer, and the electrophoretic display includes particles having a charge. The field generating electrode may receive a data signal by being connected to a switching element, such as a thin film transistor, and the electro-optical active layer displays an image by converting the data signal into an optical signal.
Recently, the display device has included a touch sensing function as well as the function for displaying the image such that it is capable of interaction with a user. A touch sensing function determines whether a user finger, etc., touches a screen, and touch position information thereof, by sensing a change of pressure, light, etc., that occurs on a screen in the display device when the user contacts the finger or a touch pen to the screen to write a character or to draw a picture. The display device may receive an image signal based on the touch information.
The touch sensing function may be realized by a touch sensor including a touch electrode. For example, in the capacitance type of touch sensor, a plurality of touch electrodes are connected to each other thereby forming a plurality of touch electrode rows and a plurality of touch electrode columns that are insulated from each other, and a driving signal is applied to each touch electrode row and each touch electrode column through a touch signal line. The touch sensor may drive the touch electrode rows and the touch electrode columns by a method using mutual capacitance formed between the touch electrode row and the touch electrode column, or a method using self-capacitance independently formed by the touch electrode rows and the touch electrode columns, respectively. However, when driving the touch sensor forming the touch electrode row and the touch electrode column by the connection of the touch electrode with the self-capacitance type, the touch sensor is driven by a unit of the electrode row and the electrode column, not the electrode unit, such that a multi-touch is not sensed by a ghost touch. The ghost touch may be understood as a position or positions on a touch panel to which no actual touch is applied, yet can be recognized by the touch sensor as having been touched.
On the other hand, the touch electrode row and the touch electrode column may be formed of a single layer or a plurality of layers. In the case of the single layer, as the touch signal lines are generally formed as numerous as the touch electrodes, an area of the touch electrodes is inevitably limited by a region occupied by the touch signal lines, and therefore touch sensitivity may also be limited.
A panel in which the touch sensor is formed is referred to as a touch panel (also as a touch sensor panel, a touch screen panel, etc.), and the display panel having the touch sensor function is also referred to as a touch panel.
The above information disclosed in this Background section is only for enhancement of understanding of the background and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.